Q2W,
Thank you. That makes sense about the head stay. Some of the used heads I've seen look like that hole is all wallowed out, or the boss has been worn badly by the stays being loose. Point taken!
I don't intend to go too crazy on this, clean and match the ports, V force reeds, pipe, etc. I've raced CR500s since 87 and love the 41 Pro series Mikuni TM from Sudco- very tuneable and tractable, good power compared to the Keihins. I intend to do mostly trail racing, no **** sand or drags.
Maybe dumb question- where is the flywheel welded- just on the rivets? Outside only? Didn't have to worry about it on the CR's for MX, so I just don't know!
Thank you, and the rest of the OGs on this site for your sharing!
And if that is a Qv2, I'd love to chat! Or if a Hall pops up... Walt

The welds need to be around the inner hub of the flywheel.  This will take the tension off the rivets holding the flywheel together.

one pipe is the QV1 and the other the QV1.1 (modded QV1 pipe to come on sooner)  His bike is in pieces after nuking his motor years ago.  Keeps claiming he'll rebuild. lol  The other doesnt seem to want to part with it either...